When the tofu skin is processed according to the normal steps, the color of the water will change slightly when soaked in water. However, if the yellow water color is too dark, it may be fake tofu skin:

1. When the tofu skin processed according to the normal steps is soaked in water, the color of the water will change slightly, but this slight color change is normal, and is the same as the tofu soaked in water that you usually see. The color is almost the same. However, if there is a very obvious yellowish or greenish cast to the tofu skin, ingredients that should not be added may be added to the tofu skin.

2. Tips for purchasing tofu skin:

1. Normal bean curd skin is as thick as a dime, with a light yellow surface and a slight luster. It is brittle and easy to break, and there is a hollow when broken into strips. The surface of the yuba added with "doubai pieces" is bright, like a layer of wax, the skin is very thin, the taste is good, and it is tough and elastic when chewed in the mouth.

2. Normal yuba is brittle and dry, easily broken and accompanied by fragments. The yuba added with borax has strong toughness and is not easy to break or boil.

3. In normal yuba, lean meat-like fibrous tissue can be seen, and the soaked water is yellow but not muddy. The yuba added with sulfur dioxide or formaldehyde has a bright color and no fibrous tissue. The water after soaking the yuba is yellow and turbid.